Diesel engines are one form of internal combustion engines, which convert chemical energy from a fossil fuel into heat energy (of combustion) into mechanical energy to produce work. In gasoline internal combustion engines, a first stroke occurs when a fuel-air mixture is allowed into the engine's cylinders via intake valves that are allowed to open via a camshaft. In a second stroke, a piston compresses a fuel-air mixture in the cylinder, creating very high temperatures and pressure. In gasoline engines, the compressed mixture is ignited by a spark from a spark plug, and the explosion generates power to push the piston in the opposite direction along the cylinder (in a third stroke). Finally, in a fourth stroke, exhaust gases are pushed out through an exhaust valve, and the process is repeated many times per second.
In a diesel engine, air is drawn into the cylinder and the inlet valve closes while the piston moves to compress the air mixture. This air is compressed to a much higher pressure than a fuel-air mixture in a gasoline engine. This greater compression of the gas generates a greater amount of heat, and diesel fuel is then injected into the very hot cylinder and the mixture spontaneously ignites without the need for an electric spark. The controlled explosion forces the piston in the opposite direction, which sends power to the wheels via a connecting rod and crankshaft and other components. To complete the cycle, gas is exhausted out the outlet valve, and the cycle repeats itself many times per second.
As a result of the excessively high temperature and pressure involved, controlling temperatures within a diesel engine is important, and various cooling systems are commonly known which attempt to do so. A typical engine cooling system uses liquid coolant (e.g., antifreeze) to cool various engine components (e.g., the cylinder head, the engine block, etc.). To achieve this, coolant is pumped around various portions of the engine compartment through hoses, and the coolant picks up heat from the engine, lubricates the water pump, and transfers the heat to a radiator, where the heat is dissipated and the coolant cooled to repeat the process. Typically, coolant is pumped via a water pump and flows from a lower radiator tank to the engine block, then to the cylinder head, and finally past a thermostat and into the upper radiator hose into the radiator. As the coolant flows down inside the radiator, the coolant loses its heat to the cooler air that is flowing past the space between the flat tubes of the radiator. By the time the coolant has reached the lower radiator tank, it has lost a considerable amount of heat and is therefore able to repeat the process as it recirculates back to the engine through its flow path.
While engine cooling systems keep temperatures of various engine components within desired temperature ranges, engine oil coolers are also known for certain engines, including diesel engines, and these coolers use the engine's cooling system to reduce the temperature of the engine oil. An engine oil cooler is a component having an oil inlet and an oil outlet wherein the oil is passed (via an oil pump) around a cooling device, typically a fluid-to-fluid heat exchanger. The two fluids involved are coolant (antifreeze) flowing within heat exchanger passages and engine oil in which the heat exchanger is immersed or in surface contact. The engine oil cooler transfers heat from the entering hot oil to the coolant via the heat exchanger contact so that the oil exiting the cooler is at an acceptable temperature to be circulated along its path for use as lubrication for the many engine components that are lubricated by the engine oil. Maintaining oil at proper operating temperatures is important for several reasons, but one reason is that the viscosity of oil is reduced as the oil temperature rises. As the oil viscosity reduces, its ability to lubricate the moving engine components is reduced. If lubrication is reduced, friction, wear, heat, and ultimately component failures can occur.
Because regulating engine oil temperature in diesel engines is important to proper functioning and long-life of the engine, it is important to ensure that the engine oil cooler is functioning properly. In some engines, most notably the 6.0 Liter diesel engines sold under the trademark Powerstroke® used in the 2003-2007 Ford® Super Duty® trucks, various types of problems are known. These particular engines are highly sensitive to engine coolant and engine oil supply and temperature problems, and some of these problems can be discovered by an increasing difference in the coolant temperature from that of the oil temperature. For a variety of reasons in these engines, the coolant side of the heat exchanger in the oil cooler has a tendency to become restricted with debris which circulates with the coolant. The small passages in the oil cooler then become restricted, which reduces the amount of coolant available to cool the engine oil. Over time, this debris significantly impedes coolant flow within the oil cooler, which eventually significantly impedes coolant from exiting the oil cooler and entering into the Exhaust Gas Recirculator (EGR) cooler downstream. The EGR is an air-to-liquid heat exchanger that uses the engine coolant to reduce exhaust gas temperatures prior to recirculating the gases through the engine's intake system. This leads to higher oil temperatures as the oil unsuccessfully attempts to properly cool and lubricate the engine systems and components (main bearings and lifters, turbocharger, high pressure oil pump, fuel injectors, etc.). Thus, a clogged or restricted oil cooler can lead to extremely expensive repairs.
The typical repair/solution for restricted/plugged oil cooler is to replace the engine oil cooler. This is a time-consuming and expensive repair. Worse is the fact that often the new oil coolers become restricted shortly after they are installed due to debris remaining in the coolant system. Both the stock oil coolers and the replacement oil coolers are closed systems having a top cover (i.e., an EGR coolant supply cover), yet have no mechanism to allow cleaning and, indeed, no reference to cleaning in the manufacturer's literature. What is needed is a solution that allows a user to reduce buildup of dirt and debris within an engine oil cooler without the need for replacing the oil cooler, and also (in situations where the existing oil cooler is itself not replaced) without the need for removing and subsequently replacing the EGR coolant supply cover every time a backflush is performed. What is needed is an apparatus and method for a backflush valve assembly that, once installed, remains installed and provides a user with the ability to backflush the engine oil cooler without ever needing to remove and replace the EGR coolant supply cover in the future.